In the papermaking industry it is becoming more common to use water jet cutting apparatus to cut notches, tails and turn-up tips into the paper web to assist in the re-threading or turn-up of the web in the next section of the papermaking machine.
Water jet tail cutters typically have a beam that extends transversely above and across the width of the web of paper. The beam has a track extending therealong and a drive mechanism for moving a carriage along the track. The carriage has an arm for supporting a water jet nozzle. The nozzle is attached to one end of a pressurized water supply hose. The water supply hose is connected at its other end to a fitting in the beam and the hose rests along the beam. When the hose is pressurized, the water jet nozzle directs a cutting jet or stream of water onto the web to cut through the web. The carriage and the nozzle move across the web to sever the web. As the carriage moves, it pulls or pushes the hose along the beam depending on the direction of movement of the carriage along the beam causing the hose to un-fold or fold in an overlapping position. In other known constructions, the hose is wrapped around a rotating drum. The drum is placed outside one end of the beam and requires a special rotatable water supply fitting connected at one end of the hose to allow the hose to rotate relative to the fitting so as not to twist the hose.
The water jet hoses are typically reinforced with flexible steel braid, and are carried in a relatively heavy "carrier" to protect, carry and guide the hose. When the hose is pressurized with water, it shrinks in length, becomes less flexible and increases in mass. While these characteristics of the pressurized hose have been resolved when the water jet carriage moves relatively slowly along the beam, the inertia associated with accelerating and decelerating the pressurized hose and carrier along the beam to high speeds increase the forces placed on the end connections of the hose and the structure of the hose carrier. Thus, this type of water jet cutting apparatus is not particularly suitable for higher cutting speed applications such as turn-up applications in high speed machines at the dry end of the machine where the speed of movement of the nozzle along the beam and across the web is critical to a successful turn-up of the web onto a new empty reel. Typically there are severe space limitations, in terms of beam length, in which to achieve high travelling speeds. In consequence, extremely high carriage accelerations and decelerations are needed in order to obtain the shortest travelling time within the available track length.
In view of the forgoing, there is a need for an improved water jet cutting apparatus which is able to achieve extremely high acceleration, speeds, and deceleration suitable for use in the turn-up applications of paper making machinery where the speed at which the water jet moves across the web is not hindered by the inertia associated with pulling or pushing a water supply hose along the beam.